Random (stupid?) question - aspirin

[sarahsunshine]

Hi all,

After all the discussion over the various new drugs, it occurred to me, why don't people use aspirin only instead of a combination Aspirin and Warfarin?

I haven't looked into the research yet, but maybe someone else can explain this to me?

 

[Mentu]

Sarah, this is certainly not a stupid question. It is actually a very important thing to know for anyone with heart issues. The simple answer is that Coumadin/Warfarin is an anti-coagulant. It acts slowly on the liver to decrease the quantity of a few key proteins in blood that normally allow blood to clot. Aspirin is an antiplatelet agent which helps prevent the small particles in the blood called "platelets" from sticking together to build a clot. Because they act in different ways, they are not interchangeable.

Aspirin can quickly help prevent the actual platelets from sticking together and can help break them apart which is why it should be one of the first things used if a person thinks they are having a heart attack. In the minutes when a heart attack is taking place, Coumadin would not have time to make any significant difference.

I think these two medications are frequently misunderstood, Sarah, so your question is far from stupid but, instead, touches on something everyone needs to understand.

Larry

 

[Protimenow]

Wow, Larry. What a great answer. I'm not being sarcastic -- I'm impressed by the clarity of the information.

One more point -- I'm now taking a low dose (81 mg) dose of aspirin at bedtime (and many others here are also taking low dose aspirin, from what I've seen), in order to add just one more layer of protection to my system. When combined with anticoagulation, slightly less sticky platelets are thought to also help retard clotting around the valves. Of course, I am not recommending that anyone should do anything without first consulting a doctor, but aspirin, for some of us, seems to be a worthwhile addition to our regimen.

(Also, it's worth remembering the warnings we all got about taking aspirin while on warfarin)

 

[yotphix]

Further to Larry's response, there are trials currently taking place to determine whether the anti-platelet action of aspirin might not itself be adequate to prevent clotting formation in patients with OnX vavles. So the question is indeed quite valid, and the answer, for some at least, is so far 'maybe'!
My own candiologist actually prescribed Warfarin on it's own, with no aspirin. It is his opinion that the additional risk of bleeding, especially internal bleeding and even more importantly subdural bleeding as a result of head injury, is not warranted by the reduction in risk of clotting that the two pronged approach provides. Given the the AHA, two other cardiologists, and the consensus opinion here on this forum disagree with him, I decided to use both but it is clear that there is still room for discussion and study on the topic of what constitutes safe and effective clot prevention.

Edit: After reading protimenow's post above, I realize that I ought to have suggested that it may not be the wisest thing to second guess your cardiologist! I've chosen to, and I'm comfortable with that decision, but I wouldn't recommend it to anyone!

 

[D.C.]

I was on both for about 2 weeks after surgery. The following week I went to ER 3 times to have my nose cauterized for nose bleeds. Stopped aspirin and about 5-10 days later all was well no nose bleeds in the last 3 years. NO aspirin for me. Seems some cardiologists like it some don't. I was warned by another cardiologist before I left the hospital.

 

[ElectLive]

For the On-X valves, I think the low-risk Aortic Valve trial arm (with no Warfarin) is not only Asprin but also Plavix - yet another anti-platelet, or "superaspirin" as some call it. To my knowledge, though, the trial results published so far have only been in the high-risk group that is using both Warfarin and Aspirin, but with INR of 1.5 to 2.0, and the interim results for stroke were actually higher (worse) than the control group (INR 2.0 - 3.5 plus also Aspirin) - but the "composite" results (both bleeding and stroke events) were more favorable (comparable). Further, for those with On-X mitral valves, the trial does not have a non-Warfarin arm.

 

[sarahsunshine]

Thanks everyone!

Now, to add to the discussion, I understand that Warfarin is an anticoagulation, and Aspirin is anti-platelet.

It was my understanding that the new drugs (Pradaxa in particular) was anti-platelet as well, which suggests that anti-platelet may be sufficient to control clotting on valve patients. Perhaps someone can clarify that too?

I also found an OLD paper where they used aspirin (with something else I can't remember) in a small group of children valve patients back in the early 80s, and aspirin did significantly reduce the number of incidents from the group that had nothing (I can't even imagine giving a child notning after getting a prosthetic heart valve!). Why did they stop using aspirin without warfarin?

 

[Lynlw]

For the On-X valves, I think the low-risk Aortic Valve trial arm (with no Warfarin) is not only Asprin but also Plavix - yet another anti-platelet, or "superaspirin" as some call it. To my knowledge, though, the trial results published so far have only been in the high-risk group that is using both Warfarin and Aspirin, but with INR of 1.5 to 2.0, and the interim results for stroke were actually higher (worse) than the control group (INR 2.0 - 3.5 plus also Aspirin) - but the "composite" results (both bleeding and stroke events) were more favorable (comparable). Further, for those with On-X mitral valves, the trial does not have a non-Warfarin arm.

You are right, there are NO aspirin only trials going on for the ON-X valve. There was one trial in Germany that was stopped before the Proact trials started after that had an aspirin only arm after someone died early on.
I think of the proact results released so far, the people with the lower INR had more Strokes and people with the "normal" INR had more Bleeds

Pradaxa inhibits thrombin, not platelets and Rivaroxaban is a factor Xa inhibitor

 

[ElectLive]

These new ones just add to the confusion. Thrombin is the blood's central clotting agent to which Pradaxa attaches itself reducing the ability of the thrombin to cause a clot. The Xa inhibitors affect another component, the interestingly named "coagulation cascade", not the thrombin, and then, well, it all just starts to go well above and beyond my capacities from there... Maybe Bill B. would like to volunteer to give us all a seminar one day?

Nothing other than Warfarin has been proven to adequately control clotting on mechanical valve patients so far, though. Different degrees of stroke prevention are being proven for other patient sets (A-Fib) but valve patients are obviously the highest risk group, and further come in different risk categories (mitral more so than aortic). Pradaxa is the only one of the new ones approaching valve trials that I'm aware of, and it's still in the earliest stages, recruiting limited numbers to target dosing only, not a full clinical trial.

Obviously, the results of the Aspirin/Plavix only On-X arm will be very interesting to see, but that may also still be recruiting. In any case, I guess the tough issue to overcome is that stroke prevention is necessary, and no matter what form, that inherently involves varying degrees of additional bleeding risk. You lower the risk of one and you raise the risk of the other. Finding the proper balance is obviously one of many challenges ahead.

 

[mtmom]

Well, I tired to post once and never found my post so will try again. Thanks for all this good info. I would like to ask another question. Why do INR levels need to be higher for a mitral valve replacement as compared to a lower INR for the aortic valve replacement? Thanks so much. Hope it was ok to jump in to this thread.

 

[neil]

good info on this one

 

[ElectLive]

Why do INR levels need to be higher for a mitral valve replacement as compared to a lower INR for the aortic valve replacement?

Major valve studies have generally shown higher stroke rates for replacement valves in the mitral position than the aortic position, so the consensus guidelines have been to anticoagulate to a higher degree. I think it primarily has to do with flow rates. There is a higher flow velocity in the aortic position so less "stoppage" potential than exists in the mitral position.

 

[sarahsunshine]

Thank you for all the great answers.

 

[Protimenow]

A few things: I often state what may sound like personal opinion (it probably is), and I suggest that you should discuss any changes with your doctor. HOWEVER, I know that many doctors are less capable of managing anticoagulation than a lot of us here are - it's OUR lives on the nine - not the doctor's or clinic's. I've been managing my INR for about three years - since I got my first meter. I keep an ongoing spreadsheet showing when I test, which meter I use (though this doesn't really matter much), INR, prothrombin time, weekly dose, and other factors that may be relevant. If my doctor wants to see it, I can easily demonstrate that I'm on top of my INR management.

The other thing -- I've been seeing commercials on TV from ambulance chasing attorneys looking for people who have used Pradaxa and had problems. This may scare some people away from Pradaxa - but there may be some acual basis for going after the Pradaxa manufacturers (because of bleeds that can't be easily stopped). I don't think this is a clever way to slow sales of Pradaxa.

For myself, I prefer to pay 10-15 cents a day to control my INR using a medication that CAN be reversed and about which there is a wealth of knowledg and decades of clinical experience.

 

[carolinemc]

When I had mine, I was on combo warafin and low dose coated asprin for 2 1/2 years. My cardio said it was some research that suggested the combo was not as badly needed. Have had no problems, so far, without the asprin. Just take tylonol for pain or fever. Hugs for everyone today.

 

[Protimenow]

I take aspirin for pain or fever - when I absolutely have to take some kind of analgesic. My use is pretty occasional. On normal days, I take one of the 81 mg aspirin, just because, and my warfarin dosing accounts for this low dose. An occasional aspirin shouldn't cause any major spikes -- unless your INR is ALREADY at the top of the range.

 

[TheGymGuy]

I love this thread. That is all